KR101320676B1 - Method of transmitting and receiving data in a multi radio access technology system and apparatus thereof - Google Patents

Abstract

The present invention relates to wireless communication, and more particularly, to a method and apparatus for transmitting and receiving data between a base station and a terminal in a multiple wireless access system.
In a method in which a terminal supporting a multi-radio access technology (Multi-RAT), which is an aspect of the present invention, performs communication, from at least one candidate cooperation terminal for client cooperation (CC) Receiving a notification signal notifying the existence of the at least one candidate cooperative terminal through a first wireless access method and at least one cooperative terminal connected through the received notification signal among the at least one candidate cooperative terminal. And transmitting first data to the base station using the first data, wherein the first data is communicated between the terminal and the at least one cooperative terminal through the first wireless access method, and the at least one cooperative terminal. The base stations may be communicated through a second wireless access scheme.

Description

METHOD OF TRANSMITTING AND RECEIVING DATA IN A MULTI RADIO ACCESS TECHNOLOGY SYSTEM AND APPARATUS THEREOF}

The present invention relates to wireless communication, and more particularly, to a method and apparatus for transmitting and receiving data between a base station and a terminal in a multiple wireless access system.

Recently, the data transmission amount of the wireless communication network is rapidly increasing. This is due to the advent and spread of various devices such as machine-to-machine (M2M) communications and smart phones and tablet PCs that require high data throughput. A carrier aggregation (CA) technique, a cognitive radio technique, and the like that efficiently use more frequency bands in order to satisfy a required high data transmission amount, a multi-antenna technique for increasing data capacity within a limited frequency, And base station cooperative transmission technology.

In addition, as the ubiquitous environment comes into the market, there is a rapid increase in the demand for providing continuous service without regard to time and place by using the equipment.

Accordingly, a plurality of terminals communicating with each other through a base station establish a cooperative system, and the wireless communication network evolves in a direction that at least one terminal cooperates to transmit or receive data according to a communication environment.

Here, a plurality of terminals are connected to other terminals in a wireless communication system, and a source device and a source device, which are subjects to communicate with a base station with the help of other terminals, Cooperative devices that act as intermediaries to provide feedback and cooperative devices other than Source Devices that do not act as cooperative devices.

A wireless communication system with high density terminals can exhibit higher system performance by cooperation between terminals. For example, in the case of transmitting predetermined data to a base station, a source device can transmit the data together with a cooperative device. Also, the source device may transmit the data through a cooperative device. The above-described example can be equally applied to a case where a base station transmits data to a terminal, thereby achieving much better system performance. Hereinafter, a wireless communication system including a plurality of terminals having a cooperative system is referred to as a Multi Radio Access Technology (RAT) system.

At this time, since a source device has mobility, it is necessary to periodically or aperiodically update information on a plurality of candidate cooperative devices existing in a location close to itself, and thus a solution for this is required.

The present invention relates to wireless communication, and more particularly, to a method and apparatus for transmitting and receiving data between a base station and a terminal in a multiple wireless access system.

An object of the present invention is to provide a method in which a terminal supporting a multi-radio access technology (Multi-RAT) performs communication.

Another technical problem to be achieved in the present invention is to provide a method for a candidate cooperative terminal that supports multi-radio access technology (Multi-RAT) to perform communication.

Another technical problem to be achieved in the present invention is to provide a method for a base station supporting multi-radio access technology (Multi-RAT) to perform communication.

Another technical problem to be achieved in the present invention is to provide a terminal supporting a multi-radio access technology (Multi-RAT (Radio Access Technology)).

Another technical problem to be achieved in the present invention is to provide a candidate cooperative terminal supporting multi-radio access technology (Multi-RAT).

Another technical problem to be achieved in the present invention is to provide a base station supporting a multi-radio access technology (Multi-RAT (Radio Access Technology)).

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

In a method of performing communication by a terminal supporting a multi-radio access technology (Multi-RAT), which is an aspect of the present invention for achieving the above technical problem, client cooperation (CC) Receiving a notification signal indicating a presence of the at least one candidate cooperation terminal from at least one candidate cooperation terminal through a first wireless access method and receiving the received notification signal of the at least one candidate cooperation terminal; And transmitting first data to the base station using at least one cooperative terminal connected through the first data, wherein the first data is communicated through the first wireless access scheme between the terminal and the at least one cooperative terminal. The at least one cooperative terminal and the base station may be communicated through a second wireless access scheme. .

The terminal may further include directly transmitting second data to the base station through the second wireless access scheme.

The first wireless access method may be a WiFi Fidelity (WiFi) access method, and the second wireless access method may be a WiMAX (Worldwide Interoperability for Microwave Access) access method.

In addition, the at least one candidate cooperative terminal may be determined by the base station.

The at least one candidate cooperative terminal may include at least one of information on whether the client cooperative operation can support a client cooperative operation, movement speed information, location information, power reserve information, channel state information, presence and number of neighboring candidate cooperative terminals, and information. It can be determined by the base station using one.

In addition, the notification signals of each of the at least one candidate cooperative terminal may be received and distinguished at different times.

The notification signal is received in the form of a ready to send (RTS) frame including a receiver address (RA) field and a transmitter address (TA) field, and the RA field distinguishes each of the at least one candidate cooperative terminal from each other. The TA field may be set to a pre-allocated address value, and the TA field may be set to a medium access control (MAC) address value of each of the at least one candidate cooperative terminal.

The terminal may further include periodically monitoring whether the notification signal has been received.

The method may further include transmitting, by the terminal, the received notification signal to the base station, wherein the received notification signal may be transmitted periodically or in response to a request received from the base station.

In the meantime, in a method in which a candidate cooperative terminal for supporting multi-radio access technology (Multi-RAT), which is an aspect of the present invention for achieving the above another technical problem, performs communication, client cooperation (Client cooperation: transmitting a notification signal for notifying the existence of the candidate cooperative terminal to a terminal through a first wireless access scheme for receiving a first data from a terminal connected through the transmitted notification signal And transmitting the received first data to the base station, wherein the first data is communicated between the terminal and the candidate cooperative terminal through the first wireless access scheme, and the candidate cooperative terminal and the base station Can be communicated via a second wireless access scheme.

The method may further include receiving an activation request message for cooperating with the client from the base station, and may transmit the notification signal to the terminal in response to the activation request message.

The method may further include receiving time information for transmitting the notification signal from the base station, wherein the notification signal may be transmitted to the terminal according to the received time information.

The notification signal may be transmitted in the form of a ready to send (RTS) frame including a receiver address (RA) field and a transmitter address (TA) field, and the RA field may be different from the candidate cooperative terminal and another candidate cooperative terminal. The TA field may be set to a pre-assigned address value for identification, and the TA field may be set to a medium access control (MAC) address value of the candidate cooperative terminal.

Meanwhile, in a method in which a base station supporting multi-radio access technology (Multi-RAT), which is an aspect of the present invention for achieving the above technical problem, performs communication, at least one candidate cooperative terminal Transmitting an activation request message for client cooperation (CC) through a second wireless access method and a notification signal for client cooperation (CC) among the at least one candidate cooperation terminal; Receiving first data using at least one cooperative terminal connected to the terminal through the first data, wherein the first data is communicated between the terminal and the at least one cooperative terminal through a first wireless access scheme; At least one cooperative terminal and the base station may communicate through the second wireless access method.

The method may further include directly receiving second data from the terminal through the second wireless access scheme.

The at least one candidate cooperative terminal may include at least one of information on whether the client cooperative operation can support a client cooperative operation, movement speed information, location information, power reserve information, channel state information, presence and number of neighboring candidate cooperative terminals, and information. It can be determined by the base station using one.

The method may further include transmitting time information for transmitting the notification signal of each of the at least one candidate cooperative terminal to the at least one candidate cooperative terminal through the second wireless access method. Each notification signal may be transmitted and distinguished at different times according to the time information.

Meanwhile, in a terminal supporting a multi-radio access technology (Multi-RAT), which is an aspect of the present invention for achieving the above technical problem, at least one for client cooperation (CC) A receiving module for receiving a notification signal indicating a presence of the at least one candidate cooperative terminal from a candidate cooperative terminal through a first wireless access method, through the received notification signal of the at least one candidate cooperative terminal; A transmission module for transmitting first data to the base station using at least one connected cooperative terminal and the first data are communicated between the terminal and the at least one cooperative terminal through the first wireless access scheme, and the at least one To control the communication between the cooperative terminal and the base station through a second wireless access method It can include documents.

Meanwhile, in a candidate cooperative terminal supporting multi-radio access technology (Multi-RAT), which is an aspect of the present invention for achieving the above technical problem, for client cooperation (CC) A transmission module for transmitting a notification signal for notifying the existence of the candidate cooperative terminal to a terminal through a first wireless access method, a reception module for receiving first data from a terminal connected through the transmitted notification signal, and the reception The first data is controlled to be transmitted to the base station through the transmitting module, and the first data is communicated between the terminal and the candidate cooperative terminal through the first radio access method, and between the candidate cooperative terminal and the base station. It may include a processor for controlling to communicate via a second wireless access scheme.

 Meanwhile, in a base station supporting a multi-radio access technology (Multi-RAT), which is an aspect of the present invention for achieving the above technical problem, client cooperation with at least one candidate cooperative terminal (Client cooperation) A transmission module for transmitting an activation request message for a CC through a second wireless access method, and connected to a terminal through a notification signal for client cooperation (CC) among the at least one candidate cooperative terminal. A receiving module for receiving first data using at least one cooperative terminal and the first data are communicated between the terminal and the at least one cooperative terminal through a first wireless access scheme, and the at least one cooperative terminal and the The base station may include a processor for controlling communication through the second wireless access scheme.

In a multi-RAT system, a base station can effectively transmit data to a source device according to the present invention. In addition, in a multi-RAT system, a source device may effectively transmit data to a base station through a cooperative device according to the present invention.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 illustrates an example of a multiple radio access system.
2 illustrates an example of multiple radio access system operations.
3 is a diagram illustrating a structure of a frequency division duplex (FDD) radio frame in 3GPP LTE.
FIG. 4 is a diagram illustrating a time division duplex (TDD) radio frame structure in 3GPP LTE. FIG.
5 illustrates an example of a resource grid for one downlink slot.
6 illustrates an example of a downlink subframe structure.
7 is a diagram illustrating a structure of an uplink subframe used in an LTE system.
8 is a diagram illustrating a mapping relationship between codewords, layers, and antennas for transmitting downlink signals in a multi-antenna wireless communication system.
9 is a view showing an example of an information exchange step required for transmitting and receiving data between a base station and a plurality of devices in a multiple radio access system in accordance with the present invention.
10 is a view showing a specific example of the transmission period of the notification signal in accordance with the present invention.
11 shows an example of a transmission frame of a notification signal in accordance with the present invention.
12 is a view showing an example of a block diagram of a base station and a terminal in accordance with the present invention.

The following description is to be understood as illustrative and not restrictive, with reference to the accompanying drawings, in which: FIG. 1 is a block diagram of a mobile communication system according to an embodiment of the present invention; And may be used in a variety of multiple access schemes as well. CDMA may be implemented in radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. The TDMA may be implemented in a wireless technology such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in wireless technologies such as IEEE (Institute of Electrical and Electronics Engineers) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, and Evolved UTRA (E-UTRA). UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution) is a part of E-UMTS (Evolved UMTS) using E-UTRA, adopting OFDMA in downlink and SC-FDMA in uplink. LTE-A (Advanced) is the evolution of LTE. IEEE 802.16m is the evolution of IEEE 802.16e.

The term 'multi-RAT' used herein may be referred to as various terms such as a wireless communication scheme.

1 is a diagram illustrating an example of a multiple radio access system.

Referring to FIG. 1, a multi-radio access system includes a base station 100 and a plurality of communication devices 110, 120, 130, and 140.

In FIG. 1, devices 110, 120, 130 and 140 indicated as communication devices are connected to other communication devices and are connected to a source device, a source device A source device that does not act as a cooperative device or a cooperative device that acts as an intermediary to help the source device communicate with the base station. have.

In a multiple wireless access system, a plurality of communication devices 110, 120, 130, and 140 may establish cooperation systems with each other. In a multi-radio access system in which a cooperative system is established, a source device can transmit data to a base station together with a cooperative device. Furthermore, the Source Device may receive data from the base station along with a cooperative device.

Here, a direct wireless communication scheme between a plurality of devices may be different from a direct wireless communication scheme between the base station and a plurality of devices. That is, data is transmitted and received by applying a wireless LAN connection method (e.g., Wi-Fi) between a plurality of devices, and a mobile communication network access method (e.g., IEEE 802.16 (WiMAX) Etc.) can be applied to transmit and receive data.

For example, a plurality of devices can directly communicate with each other according to an IEEE 802.11 (Wi-Fi) technology scheme or a Bluetooth technology scheme. On the other hand, each of the plurality of devices may directly communicate with each other using IEEE 802.16 (WiMAX) technology.

However, the present invention is not limited thereto, and a base station and a plurality of devices can communicate with each other according to the same wireless communication scheme.

Referring to FIG. 1, in a multi-radio access system in which a cooperative system is established, a source device 140 can transmit data together with a cooperating device 130 to a base station 100. As a result, the communication device can efficiently transmit data, thereby ensuring excellent performance. In addition, the throughput of each device can be enhanced through the multi-radio access system in which the cooperative system is established, and the effect of reducing the power consumption through the data communication through the cooperative system is also guaranteed.

Also, in a multi-radio access system in which a cooperative system is established, a source device can transmit data to a base station through a cooperative device. Furthermore, the Source Device may receive data from the base station via a cooperative device.

Referring to FIG. 1, in a multi-radio access system in which a cooperative scheme is established, a source device 110 can transmit data to a base station 100 through a cooperative device 120. This allows the communication device to efficiently transmit data, thereby preventing deterioration of system performance.

1, an example in which a source device transmits data to a base station via a cooperative device has been described. However, the same can be applied to the case where a base station receives data from a source device.

1 may be a cooperating device or a neighboring device not participating in the transmission of data, and the cooperating devices 120 and 130 may also be a source device or data Lt; RTI ID = 0.0 > of < / RTI >

2 is a diagram showing an example of the operation of a multiple radio access system.

Referring to FIG. 2, a multi-radio access system includes a base station 210 and a plurality of communication devices 220 and 230.

In the multiple wireless access system, a plurality of communication devices 220 and 230 can establish cooperative systems with each other through a wireless technology such as 802.11 (Wi-Fi).

Each of the plurality of communication devices 220 and 230 may transmit or receive data directly via the base station 210 and a wireless technology such as IEEE 802.16 (WiMAX).

At this time, if the current communication quality of the source device 220 suddenly drops, the source device 220 can indirectly transmit the data to the base station 210 through the cooperation device 230.

Accordingly, in a multi-radio access system, a communication device can directly communicate data directly with a base station, indirectly communicate with the help of a cooperative device having excellent communication quality, Deterioration can be prevented and efficient data communication can be performed.

In a multi-radio access system, in order for a plurality of communication devices to cooperate with each other to transmit and receive data, a preliminary procedure for exchanging information in advance is required.

In the multi-radio access system, information exchange steps to be performed between a base station and a plurality of communication devices can be roughly classified into four steps. That is, it may include a general network entry step, a negotiation step for cooperation of a plurality of devices, a search for a neighboring device of the source device, a selection of a cooperating device among the discovered neighboring devices, and a connection to the selected cooperating device .

Next, a structure of a radio frame that can be applied to the present invention will be described.

For convenience of description, a structure of a radio frame applied in 3GPP LTE will be described as an example, but the content of the present invention is not limited thereto, and various types of radio frames may be applied.

3 shows a structure of a frequency division duplex (FDD) radio frame in 3GPP LTE. This radio frame structure is referred to as frame structure type 1.

Referring to FIG. 3, a radio frame consists of 10 subframes, and one subframe is defined as two consecutive slots. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). The length of time of the radio frame is T _f = 307 200 * T _s = 10 ms and consists of 20 slots. The length of time of the _slot T _slot = 15360 * T _s = 0.5ms, numbered from 0 to 19. Downlink, where each node or base station transmits a signal to a terminal, and uplink, which a terminal transmits a signal to each node or base station, are distinguished in a frequency domain.

4 shows a time division duplex (TDD) radio frame structure in 3GPP LTE. This radio frame structure is referred to as frame structure type 2.

Referring to FIG. 4, one radio frame is composed of two half-frames having a length of 10 ms and a length of 5 ms. One half frame also consists of five subframes having a length of 1 ms. One subframe is designated as one of an uplink subframe (UL subframe), a downlink subframe (DL subframe), and a special subframe. One radio frame includes at least one uplink subframe and at least one downlink subframe. One subframe is defined by two consecutive slots. For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms.

The special subframe is a specific period for separating the uplink and the downlink between the uplink subframe and the downlink subframe. At least one special subframe exists in one radio frame, and the special subframe includes a downlink pilot time slot (DwPTS), a guard period, and an uplink pilot time slot (UpPTS). DwPTS is used for initial cell search, synchronization or channel estimation. UpPTS is used to match the channel estimation at the base station and the uplink transmission synchronization of the terminal. The guard interval is a period for eliminating the interference occurring in the uplink due to the multi-path delay of the downlink signal between the uplink and the downlink.

One slot in the FDD and TDD radio frames includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain and includes a plurality of resource blocks (RBs) in the frequency domain. The OFDM symbol is used to represent one symbol period since 3GPP LTE uses OFDMA in downlink, and may be called another term such as an SC-FDMA symbol according to a multiple access scheme. The RB includes a plurality of consecutive subcarriers in one slot in resource allocation units.

The structure of the radio frame described with reference to FIGS. 3 and 4 is 3GPP TS 36.211 V8.3.0 (2008-05) "Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release) 8) "and sections 4.1 and 4.2.

The structure of the above-described radio frame is merely an example, and the number of subframes included in the radio frame or the number of slots included in the subframe and the number of OFDM symbols included in the slot may be variously changed.

5 is an exemplary diagram illustrating a resource grid for one downlink slot.

Referring to FIG. 5, one downlink slot includes a plurality of OFDM symbols in a time domain. Here, one downlink slot includes 7 OFDMA symbols, and one resource block (RB) is exemplarily described as including 12 subcarriers in a frequency domain, but is not limited thereto.

Each element on the resource grid is called a resource element, and one resource block RB includes 12 × 7 resource elements. The number N ^DL of resource blocks included in the downlink slot is dependent on the downlink transmission bandwidth set in the cell. The resource grid for the downlink slot described above may also be applied to the uplink slot.

6 shows an example of a downlink subframe structure.

Referring to FIG. 6, a subframe includes two consecutive slots. Up to three OFDM symbols of the first slot in the subframe may be a control region to which downlink control channels are allocated, and the remaining OFDM symbols may be a data region to which a Physical Downlink Shared Channel (PDSCH) is allocated.

The downlink control channel includes a PCFICH (Physical Control Format Indicator Channel), a PDCCH (Physical Downlink Control Channel), PHICH (Physical Hybrid-ARQ Indicator Channel). The PCFICH transmitted in the first OFDM symbol of the subframe carries information about the number of OFDM symbols (that is, the size of the control region) used for transmission of control channels in the subframe. The control information transmitted through the PDCCH is referred to as downlink control information (DCI). DCI indicates uplink resource allocation information, downlink resource allocation information, and uplink transmit power control command for certain UE groups. The PHICH carries an ACK (Acknowledgement) / NACK (Not-Acknowledgement) signal for a hybrid automatic repeat request (HARQ) of uplink data. That is, the ACK / NACK signal for the uplink data transmitted by the UE is transmitted on the PHICH.

PDSCH is a channel through which control information and / or data is transmitted. The UE may read down the data transmitted through the PDSCH by decoding the downlink control information transmitted through the PDCCH.

7 is a diagram illustrating a structure of a UL subframe used in an LTE system.

Referring to FIG. 7, a subframe 700 having a length of 1 ms, which is a basic unit of LTE uplink transmission, is composed of two 0.5 ms slots 701. Assuming the length of a normal cyclic prefix (CP), each slot is composed of seven symbols 702 and one symbol corresponds to one SC-FDMA symbol. The resource block 703 is a resource allocation unit corresponding to 12 subcarriers in the frequency domain and one slot in the time domain. The structure of the uplink subframe of LTE is largely divided into a data region 704 and a control region 705. Here, the data area means a series of communication resources used in transmitting data such as voice and packet transmitted to each terminal, and corresponds to the remaining resources except for the control area in the subframe. The control region means a series of communication resources used for transmitting downlink channel quality reports from each terminal, reception ACK / NACK for downlink signals, and uplink scheduling requests.

As shown in the example of FIG. 7, an area 706 in which a sounding reference signal can be transmitted in one subframe is an interval in which one SC-FDMA symbol is located last on the time axis in one subframe. It is transmitted through the data transmission band. Sounding reference signals of various terminals transmitted in the last SC-FDMA of the same subframe can be distinguished from cyclic shift values. In addition, an area in which a DM (Demodulation) -Reference Signal is transmitted in one subframe is a section including a center SC-FDMA symbol, that is, a fourth SC-FDMA symbol and an eleventh SC-FDMA symbol in one slot. It is transmitted through the data transmission band on the frequency.

8 is a diagram illustrating a mapping relationship between codewords, layers, and antennas for transmitting downlink signals in a multi-antenna wireless communication system.

Referring to FIG. 8, there is a complex mapping relationship between data information and transmitted symbols. First, as the data information, the MAC layer transmits N _C transport blocks to the physical layer, and the transport blocks in the physical layer are converted into codewords through a channel coding process, and are puncturing or repetition. The same rate matching as the procedure is performed. The channel coding is performed here in a channel coder such as a turbo encoder or tail bit convolutional encoder.

와 같이 표현할 수 있다. H는 채널 행렬을 의미한다.After channel coding and rate matching, N _C codewords are mapped to N _L layers. In this case, the layers refer to different pieces of information sent by using a multi-antenna technology, and the number of layers cannot be greater than the rank, which is the maximum number of different pieces of information. This is a formula

Can be expressed as H means a channel matrix.

For reference, unlike Orthogonal Frequency Division Multiple Access (OFDMA) transmission, which is a general downlink transmission method, an uplink signal transmitted in Single Carrier-Frequency Division Multiple Access (SC-FDMA) method is processed with Inverse Fast Fourier Transform (IFFT). In order to partially offset the influence so that the transmission signal has a single carrier characteristic, a DFT process is performed for each layer.

In each layer, the DFT-converted signal is multiplied by a precoding matrix and mapped to N _T transmit antennas, and then transmitted to the base station through an IFFT process.

In general, a common reference signal and a UE specific reference signal exist in the downlink reference signal, and precoding is not applied to the common reference signal. That is, on the other hand, the terminal specific reference signal is inserted at the front end of the precoding, precoded and transmitted to the terminal side in the same manner as general data.

There are some constraints for implementing channel-independent spatial multiplexing transmission using UE specific reference signals, that is, dedicated reference signals. First, in order to reduce the signaling overhead of the reference signal, the transmission reference signal should be precoded using the same precoding matrix as the modulated data symbol. In addition, to obtain spatial channel diversity, the precoding matrix must be switched between antennas. However, since the dedicated reference signal is transmitted in a specific rule or arbitrarily over the entire transmission resource region, it is not easy to satisfy the constraint. This is because the channel measurement is performed in units of a certain number of resource elements for the efficiency of channel measurement. Thus, the precoding matrix for precoding a dedicated reference signal cannot be changed in units of resource elements.

On the other hand, in a multiple wireless access system, a plurality of communication devices cooperate in advance and require a preliminary procedure of exchanging information in advance.

At each step of the information exchange pre procedure each communication device may be in three states. That is, it may be placed in a first state not connected to each other, a second state in which the other communication device is recognized and authenticated, and a third state in combination with the other communication device.

This will be described in detail with reference to Table 1.

certification( Authentication ) Combination( Association ) State 1 X X State 2 O X State 3 O O

First, the first state means a state in which a plurality of communication devices are not connected at all in the multiple radio access system. Therefore, in the first state, each source device must communicate data directly with the base station.

Next, the second state means a state of acquiring information of the counterpart communication device and authenticating the counterpart communication device.

An example of a method of acquiring information of the counterpart communication device is a passive method of receiving information of the counterpart communication device through a beacon message or a probe request message is transmitted and received in response to the transmitted probe request message. An active method for receiving information of the counterpart communication device through the probe response message may be used.

Each communication device acquires the information of the other communication device using the above-described method, and then exchanges an authentication frame with the other communication device (for example, an authentication request and an authentication response) to perform an authentication check operation. To complete.

Each communication device enters a second state when the authentication check operation is completed.

Finally, the third state means a state combined with an authenticated counterpart communication device.

That is, each communication device exchanges an association frame with a counterpart communication device (eg, an association request and an association response) to complete an association operation (eg, AID assignment, etc.). When the combining operation of the plurality of communication devices in the wireless access system is completed, these communication devices may transmit and receive data with each other.

In the above, the state of the communication devices in each step of the information exchange preliminary procedure has been described. Hereinafter, to facilitate the understanding of the present invention, each step of the information exchange pre procedure in the radio access system including the base station will be described in detail.

Basically, in the multi-radio access system, the information exchange step to be performed between the base station and the plurality of communication devices can be largely composed of four steps. That is, it may include a general network entry step, a negotiation step for cooperation of a plurality of devices, a search for a neighboring device of the source device, a selection of a cooperating device among the discovered neighboring devices, and a connection to the selected cooperating device .

Hereinafter, for convenience of description, it is assumed that each step subject of the information exchange pre- procedure is a source device. However, the content of the present invention is not limited thereto, and the content of the present invention may be applied to devices, cooperative devices, candidate cooperative devices, and the like, which support multiple radio access systems in each step.

9 is a view showing an example of the information exchange step required for transmitting and receiving data between a base station and a plurality of devices in a multi-radio access system in accordance with the present invention.

First, the source device goes through the base station and the general network entry step (S1000). That is, through the general network entry step (S1000), the source device may be connected to the base station to directly transmit and receive data. For convenience of description, the general network entry step S1000 is hereinafter referred to as first step.

Next, the source device, which has undergone the first step with the base station, goes through a negotiation step (S2000) for cooperating a plurality of devices in the multiple radio access system. In the negotiation step S2000, the source device negotiates with the base station about the capability for cooperative operation.

In this case, the information that can be transmitted and received between the base station and the source device may include connection RAT type information, system type information, system version information, location information, information on whether the role of the cooperative device can perform.

For convenience of explanation, the negotiation step S2000 is referred to as a second step hereinafter.

Next, the base station, the source device, and the plurality of candidate cooperative devices, which have passed through the second step, search for neighboring devices and select a cooperative device among the discovered neighboring devices (S3000). For convenience of explanation, the step of searching for a neighboring device and selecting a cooperative device among the found neighboring devices (S3000) is hereinafter referred to as a third step.

In the third step, the base station, the source device and the plurality of candidate cooperative devices exchange location information with each other, and select a cooperative device to participate in data communication in the multiple radio access system based on this.

The source device having passed through the third step is connected to the selected cooperative device (S4000). When the step (S4000) of connecting with the selected cooperative device is completed, the connected source device and the cooperative device may cooperate with each other to transmit and receive data with the base station.

Hereinafter, for convenience of description, the step S4000 of connecting with the selected cooperative device will be referred to as a fourth step.

In this case, each step of the information exchange pre procedure may not be applied to all communication devices in common.

That is, the first step and the second step should be performed in common by a plurality of communication devices supporting the multiple radio access system. However, the third and fourth steps may be performed by at least one of the source device, the cooperative device, or the candidate cooperative device, and not all communication devices need to perform the third and fourth steps.

However, some processes of the third step (for example, obtaining location information of each of the plurality of communication devices supporting the multi-radio access system) may need to be performed by all communication devices in common.

Therefore, all communication devices supporting the multi-radio access system must go through the first step and the second step, so that the communication devices that have passed the first step and the second step are not distinguished from each other. After the third step, the device is treated as a preliminary source device and a preliminary cooperative device. After the fourth step is completed, the source device and the cooperative device may be determined to cooperate with each other to transmit and receive data with the base station.

Meanwhile, the source device searches for a plurality of candidate cooperating devices capable of performing client cooperation in order to perform efficient data communication with the base station, and selects at least one cooperating device from the found plurality of candidate cooperating devices. Perform a Client Cooperation operation.

In this case, since the source device has mobility, it is necessary to periodically or aperiodically update information on a plurality of candidate cooperative devices existing in a location close to the source device. This is because when the location of the source device or the cooperative device is changed, a plurality of candidate cooperative devices capable of performing client cooperation with the source device may also be changed.

In order to solve the above problems, the present invention transmits a notification signal for notifying a presence of a plurality of candidate cooperation devices capable of performing client cooperation, and the source device receiving the same. The present invention provides a method of identifying information about a plurality of candidate cooperative devices existing at a location close to a current location through a notification signal received by the controller.

In the following description, client cooperation or enhanced tethering operation in a multiple wireless access system is referred to as CC operation for convenience of description.

Prior to describing a specific method of transmitting a notification signal for notifying a presence of a plurality of candidate cooperative devices, a method of determining a plurality of candidate cooperative devices capable of performing a CC operation with a source device is described. do.

A plurality of candidate cooperative devices capable of performing CC operation with the source device may be determined by the base station.

The base station may include information on whether CC can support CC operation in a multiple radio access system (eg, support information), movement speed information (eg, floating, moving at low speed), location information, Whether the device can perform CC operation with the source device in consideration of the existence and number of candidate cooperative devices in the vicinity, power reserve information, and channel state information (for example, high quality state). Judge for.

In this case, the base station may request transmission of the remaining information from the corresponding device only when some information among the plurality of listed information satisfies the condition for performing the CC operation with the source device.

For example, only when the channel state of the corresponding device supporting CC operation in a multi-radio access system is good, the base station can determine the remaining information such as moving speed information, location information, existence and number of neighboring candidate cooperative devices, and power. The corresponding device may request to transmit the reserve information.

In this case, when the base station satisfies a condition for performing the CC operation with the source device and determines that the CC operation is necessary, the base station requests the corresponding device to perform a role as a candidate cooperative device.

The corresponding device that receives the request to perform a role as a candidate cooperative device from the base station may approve or reject it.

If the device approves the request to perform the role of a candidate cooperative device received from the base station, the device may provide specific information (eg, IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11) to perform the CC operation. n information about the system type, system version, MAC address, WiFi, or Bluetooth in the wireless technology) is transmitted to the base station.

Subsequently, when specific information necessary for performing the CC operation is transmitted to the base station, the corresponding device may serve as a candidate cooperative device.

Hereinafter, assuming that a plurality of candidate cooperative devices have been determined by the base station, a specific method of transmitting a notification signal to the source device for notifying the presence of the plurality of candidate cooperative devices will be described.

First, each of the plurality of candidate cooperative devices transmits a notification signal at the same time point as neighboring candidate cooperative devices, so as to avoid the overlapping of the transmitted notification signals, the transmission period of the base station and the notification signal. , Transmission offset, etc. can be negotiated. Such negotiation may also take place in the request process for each device to be determined as a candidate cooperative device.

In addition, the start point of the notification signal transmission period may be defined as a specific point in time such as when the negotiation is completed.

FIG. 10 is a diagram illustrating a specific example of a transmission period of a notification signal according to the present invention. FIG.

First, FIG. 10A illustrates a transmission period of a notification signal according to a point coordination function (PCF).

Referring to FIG. 10A, the entire PCF includes a plurality of transmission periods, and each transmission period includes a plurality of contention periods and contention-free periods.

In the contention period, each of the plurality of candidate cooperative devices freely transmits its own notification signal to the outside.

However, in the contention-free period, only a candidate cooperative device designated to transmit a notification signal to the contention-free period in agreement with the base station may transmit its own notification signal. Send to outside.

Therefore, the point coordination function (PCF) is based on a contention period, but by using a contention-free period together, it is possible to solve the problem of overlapping the transmitted notification signals.

In addition, a notification signal may be transmitted according to a distributed coordination function (DCF) configured only with a contention period.

Referring to FIG. 10B, the entire DCF is composed of a plurality of transmission periods, and each transmission period includes a plurality of contention periods.

In the contention period, each of the plurality of candidate cooperative devices freely transmits its own notification signal to the outside.

Therefore, in the point coordination function (DCF), based on the contention period, each candidate cooperative device frequently gives an opportunity to transmit a notification signal so that the transmitted notification signals can be efficiently transmitted to the source device. You may.

Hereinafter, a detailed frame of the notification signal transmitted by each of the plurality of candidate cooperative devices will be described.

Each of the plurality of candidate cooperative devices periodically announces its presence to other neighboring devices in a multicast manner.

When WiFi technology is applied to the multiple wireless access system, a notification signal transmitted from each of the plurality of candidate cooperative devices may be a ready to send (RTS) frame.

In this case, as described above, in order to prevent collision or interference with neighboring candidate cooperative devices, the candidate cooperative device transmitting the notification signal may transmit the corresponding RTS at a period and a time point negotiated with the base station. .

In addition, the candidate cooperative device may determine the transmission time of the RTS by a conventional contention resolution method.

FIG. 11 is a diagram illustrating an example of an RTS transmission frame for a notification signal when WiFi technology is applied to a multiple wireless access system according to the present invention.

The RTS transmission frame for the notification signal may include a frame control field, a duration field, a receiver address field, a transmitter address field, a frame check sum (FCS) field, and the like.

At this time, each field in the RTS transmission frame may be set as follows.

First, the RA (Receiver Address) field may be set to a value of a multicast-group address in order for other devices to determine the existence of candidate cooperative devices.

The multicast group address value for the purpose is occupied in advance, and all devices supporting the CC operation already know the multicast-group address value. Therefore, through the RA (Receiver Address) field in the RTS transmission frame, It can be seen that the frame includes a frame including information (eg, MAC address) of candidate cooperative devices.

Next, the TA (Transmitter Address) field may be set to the MAC address value of the candidate cooperative device itself.

In addition, when the RTS transmission frame is transmitted for the notification signal, another operation such as CTS is not required, so the duration field may be set to zero.

However, the RTS transmission frame described with reference to FIG. 11 is merely an example of a frame for transmitting the notification signal and may have another form.

For example, the frame for transmitting the notification signal may include only a frame control field, a receiver address field, a transmitter address field, and a frame check sum (FCS) field.

In addition, the RTS transmission frame is utilized when a WiFi technology is applied to a multiple wireless access system, and when a wireless technology such as IEEE 802.16 (WiMAX), IEEE 802.20, and E-UTRA (Evolved UTRA) is applied. Other types of notification signal transmission frames may be utilized.

Hereinafter, a specific method of monitoring a notification signal by another device will be described.

A general device (eg, a source device) supporting the CC operation monitors a notification signal that can be transmitted from neighboring candidate cooperative devices.

In this case, the source device may periodically perform an operation of monitoring a notification signal to maintain a list of information on the latest candidate cooperative device.

If the WiFi technology is applied to the multi-radio access system, the source device may receive an RTS transmission frame in which a multicast-group address value is set in a receiver address field in association with a notification signal. .

When the notification signal is received through the RTS transmission frame, the source device does not transmit the CTS to devices having a transmitter address (TA) field in the RTS transmission frame.

At this time, the source device updates the candidate cooperative device information list for performing the CC operation by using a TA (Transmitter Address) field in the received RTS transmission frame.

If the notification signal is not received from the candidate cooperation device included in the existing candidate cooperation device information list for a preset period, the source device may exclude the candidate cooperation device from which the notification signal is not received from the list.

The source device may periodically report the latest candidate cooperative device information list to the base station or report in response to a request of the base station.

In addition, when the base station determines that there is a change in the received information list, the base station may transmit the change to the corresponding source device.

Therefore, a mobile source device can periodically or aperiodically update information on a plurality of candidate cooperative devices that are located close to its own through a notification signal, thereby smoothing client cooperation. Can be done.

12 is a diagram illustrating a configuration of a preferred embodiment of a base station apparatus 1210 and a communication apparatus 1220 supporting a multiple radio access system according to the present invention. In the above description, terms used for a terminal, a communication device, and a communication device are used interchangeably, but hereinafter, a terminal device will be described to prevent confusion.

Referring to FIG. 12, the base station apparatus 1210 according to the present invention may include a receiving module 1211, a transmitting module 1212, a processor 1213, a memory 1214, and a plurality of antennas 1215. . The plurality of antennas 1215 refers to a base station apparatus supporting MIMO transmission and reception. The receiving module 1211 can receive various signals, data, and information on the uplink from the terminal. The transmission module 1212 can transmit various signals, data, and information on the downlink to the terminal. The processor 1213 may control the overall operation of the base station apparatus 1910.

The processor 1213 of the base station apparatus 1210 may determine a plurality of candidate cooperative devices capable of performing CC operation with the source device. That is, the processor 1213 of the base station apparatus 1210 can provide information on whether CC operation can be supported in a multiple radio access system (eg, support information), and movement speed information (eg, floating). , Low speed, etc.), location information, presence and number of candidate cooperative devices in the vicinity, power reserve information, channel state information (for example, high quality state), etc. It is determined whether the CC operation can be performed with the source device.

In addition, the processor 1213 of the base station apparatus 1210 performs a function of processing the information received by the base station apparatus 1210, information to be transmitted to the outside, and the memory 1214. And may be replaced by a component such as a buffer (not shown).

Referring to FIG. 12, the terminal device 1220 according to the present invention may include a receiving module 1221, a transmitting module 1222, a processor 1223, a memory 1224, and a plurality of antennas 1225. The plurality of antennas 1225 refers to a terminal device that supports MIMO transmission / reception. The receiving module 1221 can receive various signals, data, and information on the downlink from the base station. The receiving module 1222 may transmit various signals, data, and information on the uplink to the base station. The processor 1223 can control the operation of the entire terminal device 1220. [

The processor 1223 of the terminal device 1220 transmits a corresponding notification signal at a period and a time point negotiated with a base station to prevent collision or interference with a neighboring candidate cooperative device. Can be controlled.

In addition, the processor 1223 of the terminal device 1220 monitors a notification signal that may be transmitted from neighboring candidate cooperative devices. In this case, in order to maintain a list of information on the latest candidate cooperative devices, the controller may periodically perform an operation of monitoring a notification signal.

The processor 1223 of the terminal device 1220 also performs a function of calculating information received by the terminal device 1220 and information to be transmitted to the outside and the memory 1224 stores the processed information and the like at a predetermined time And may be replaced by a component such as a buffer (not shown).

The specific configuration of the base station apparatus and the terminal apparatus may be implemented such that the above-described embodiments of the present invention are applied independently or two or more embodiments may be simultaneously applied. For the sake of clarity, It is omitted.

In addition, in the description of FIG. 12, the description of the base station apparatus 1210 may be equally applicable to a relay apparatus as a downlink transmitting entity or an uplink receiving entity, and the description of the terminal device 1220 may be used for downlink reception. The same may be applied to the relay apparatus as a subject or an uplink transmission subject.

The above-described embodiments of the present invention can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof.

For implementation in hardware, a method according to embodiments of the present invention may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), and Programmable Logic Devices (PLDs). It may be implemented by field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In the case of an implementation by firmware or software, the method according to embodiments of the present invention may be implemented in the form of a module, a procedure or a function for performing the functions or operations described above. The software code can be stored in a memory unit and driven by the processor. The memory unit may be located inside or outside the processor, and may exchange data with the processor by various well-known means.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The foregoing description of the preferred embodiments of the invention disclosed herein has been presented to enable any person skilled in the art to make and use the present invention. While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. For example, those skilled in the art can utilize each of the configurations described in the above-described embodiments in a manner of mutually combining them. Accordingly, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the invention should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the invention are included in the scope of the invention. The present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. In addition, claims that do not have an explicit citation in the claims can be combined to form an embodiment or included as a new claim by amendment after the application.

Claims (20)

In a method of performing communication by a terminal supporting a multi-radio access technology (Multi-RAT),
Receiving a notification signal indicating a presence of the at least one candidate cooperating terminal from at least one candidate cooperating terminal through a first wireless access scheme for client cooperation (CC); And
Transmitting first data to a base station by using at least one cooperative terminal connected through the received notification signal among the at least one candidate cooperative terminal,
The first data is communicated between the terminal and the at least one cooperative terminal through the first radio access method, and the at least one cooperative terminal and the base station are communicated through a second radio access method. How to perform communication. The method of claim 1,
And transmitting, by the terminal, the second data directly to the base station through the second wireless access scheme. The method of claim 1,
And the first wireless access method is a WiFi Fidelity (WiFi) connection method, and the second wireless access method is a WiMAX (Worldwide Interoperability for Microwave Access) connection method. The method of claim 1,
And the at least one candidate cooperative terminal is determined by the base station. 5. The method of claim 4,
The at least one candidate cooperative terminal,
What is determined by the base station using at least one of information on whether the client cooperation operation can be supported, moving speed information, location information, power reserve information, channel state information, the presence and number of neighboring candidate cooperative terminal Characterized in that the method of performing communication. The method of claim 1,
And the notification signal of each of the at least one candidate cooperative terminal is received and distinguished at different times. The method of claim 1,
The notification signal is received in the form of a ready to send (RTS) frame including a receiver address (RA) field and a transmitter address (TA) field.
The RA field is set to a pre-assigned address value to distinguish each of the at least one candidate cooperative terminal from each other, and the TA field is set to a medium access control (MAC) address value of each of the at least one candidate cooperative terminal. Characterized in that the communication method. The method of claim 1,
And monitoring, by the terminal, periodically whether the notification signal has been received. The method of claim 1,
The terminal further comprises the step of transmitting the received notification signal to the base station,
The received notification signal is periodically transmitted or transmitted in response to the request received from the base station, characterized in that the communication. In the method for the candidate cooperative terminal that supports a multi-radio access technology (Multi-RAT) to perform communication,
Transmitting a notification signal notifying the existence of the candidate cooperative terminal to a terminal through a first wireless access method for client cooperation (CC);
Receiving first data from a terminal connected through the transmitted notification signal; And
Transmitting the received first data to a base station;
And the first data is communicated between the terminal and the candidate cooperative terminal through the first radio access method, and is communicated between the candidate cooperative terminal and the base station through a second radio access method. The method of claim 10,
Receiving an activation request message for client cooperation from the base station,
And transmitting the notification signal to the terminal in response to the activation request message. The method of claim 10,
Receiving time information for transmitting the notification signal from the base station,
And the notification signal is transmitted to the terminal according to the received time information. The method of claim 10,
The notification signal is transmitted in the form of a ready to send (RTS) frame including a receiver address (RA) field and a transmitter address (TA) field.
The RA field is set to an address value pre-assigned to distinguish the candidate cooperative terminal from another candidate cooperative terminal, and the TA field is set to a medium access control (MAC) address value of the candidate cooperative terminal. How to perform communication. In a method for communication by a base station supporting a multi-radio access technology (Multi-RAT),
Transmitting an activation request message for client cooperation (CC) to at least one candidate cooperative terminal through a second wireless access method; And
Receiving first data using at least one cooperative terminal connected to the terminal through a notification signal for client cooperation (CC) among the at least one candidate cooperative terminal,
The first data is communicated between the terminal and the at least one cooperative terminal through a first radio access method, and the at least one cooperative terminal and the base station are communicated through the second radio access method. How to perform communication. The method of claim 14,
And directly receiving second data from the terminal through the second wireless access scheme. The method of claim 14,
The at least one candidate cooperative terminal,
What is determined by the base station using at least one of information on whether the client cooperation operation can be supported, moving speed information, location information, power reserve information, channel state information, the presence and number of neighboring candidate cooperative terminal Characterized in that the method of performing communication. The method of claim 14,
Transmitting the time information for transmitting the notification signal of each of the at least one candidate cooperative terminal to the at least one candidate cooperative terminal through the second wireless access method,
And a notification signal of each of the at least one candidate cooperative terminal is transmitted and distinguished at different times according to the time information. In a terminal supporting a multi-radio access technology (Multi-RAT),
A receiving module for receiving a notification signal indicating a presence of the at least one candidate cooperative terminal from a at least one candidate cooperative terminal through a first wireless access scheme for client cooperation (CC);
A transmission module for transmitting first data to a base station by using at least one cooperative terminal connected through the received notification signal among the at least one candidate cooperative terminal; And
And a processor configured to control the first data to be communicated between the terminal and the at least one cooperative terminal through the first radio access method, and to communicate between the at least one cooperative terminal and the base station through a second radio access method. Terminal. In a candidate cooperative terminal supporting multiple radio access technologies (Multi-RAT (Radio Access Technology)),
A transmission module for transmitting a notification signal notifying the existence of the candidate cooperation terminal to a terminal through a first wireless access method for client cooperation (CC);
A receiving module which receives first data from a terminal connected through the transmitted notification signal; And
The received first data is controlled to be transmitted to a base station through the transmitting module, and the first data is communicated between the terminal and the candidate cooperative terminal through the first radio access method, and the candidate cooperative terminal and the base station And a processor for controlling the communication to be communicated via a second wireless access scheme. In the base station supporting a multi-radio access technology (Multi-RAT),
A transmitting module for transmitting an activation request message for client cooperation (CC) to at least one candidate cooperative terminal through a second wireless access scheme;
A receiving module configured to receive first data using at least one cooperative terminal connected to the terminal through a notification signal for client cooperation (CC) among the at least one candidate cooperative terminal; And
And a processor configured to control the first data to be communicated between the terminal and the at least one cooperative terminal through a first wireless access scheme, and to communicate between the at least one cooperative terminal and the base station through the second wireless access scheme. Base station.

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